6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Guillaume Nault gnault@redhat.com
commit 4e914ef063de40397e25a025c70d9737a9e45a8c upstream.
Use addrconf_add_dev() instead of ipv6_find_idev() in addrconf_gre_config() so that we don't just get the inet6_dev, but also install the default ff00::/8 multicast route.
Before commit 3e6a0243ff00 ("gre: Fix again IPv6 link-local address generation."), the multicast route was created at the end of the function by addrconf_add_mroute(). But this code path is now only taken in one particular case (gre devices not bound to a local IP address and in EUI64 mode). For all other cases, the function exits early and addrconf_add_mroute() is not called anymore.
Using addrconf_add_dev() instead of ipv6_find_idev() in addrconf_gre_config(), fixes the problem as it will create the default multicast route for all gre devices. This also brings addrconf_gre_config() a bit closer to the normal netdevice IPv6 configuration code (addrconf_dev_config()).
Cc: stable@vger.kernel.org Fixes: 3e6a0243ff00 ("gre: Fix again IPv6 link-local address generation.") Reported-by: Aiden Yang ling@moedove.com Closes: https://lore.kernel.org/netdev/CANR=AhRM7YHHXVxJ4DmrTNMeuEOY87K2mLmo9KMed1JM... Reviewed-by: Gary Guo gary@garyguo.net Tested-by: Gary Guo gary@garyguo.net Signed-off-by: Guillaume Nault gnault@redhat.com Reviewed-by: Ido Schimmel idosch@nvidia.com Link: https://patch.msgid.link/027a923dcb550ad115e6d93ee8bb7d310378bd01.1752070620... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/addrconf.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
--- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3525,11 +3525,9 @@ static void addrconf_gre_config(struct n
ASSERT_RTNL();
- idev = ipv6_find_idev(dev); - if (IS_ERR(idev)) { - pr_debug("%s: add_dev failed\n", __func__); + idev = addrconf_add_dev(dev); + if (IS_ERR(idev)) return; - }
/* Generate the IPv6 link-local address using addrconf_addr_gen(), * unless we have an IPv4 GRE device not bound to an IP address and @@ -3543,9 +3541,6 @@ static void addrconf_gre_config(struct n }
add_v4_addrs(idev); - - if (dev->flags & IFF_POINTOPOINT) - addrconf_add_mroute(dev); } #endif